There is a risk of exposure to infectious agents by health care workers who are continually utilizing hypodermic syringe assemblies for injecting patients with medicaments. Because of this risk, needles used by health care workers are regarded as potentially infective and are handled with extraordinary care to prevent accidental injuries. Health care workers are advised to place disposable needles in the puncture resistant containers. It has become more convenient and safe to provide capping assemblies secured to each needle for immediate capping after use of the needle.
U.S. Pat. No. 3,134,380 to Armao, issued May 26, 1964 is representative and relates to a hypodermic needle assembly which attempts to shield a used hypodermic needle after use. The Armao patent discloses a retractable needle guard which extends over the length of the needle assembly prior to use and is retracted as the needle is inserted into the patient
This typical assembly includes a shield which covers a significant portion of the needle shaft during use of the needle for an injection. Hence, the typical assemblies either have less usable needle length if a conventional needle is adapted to the assembly, or the assemblies require a significantly longer needle shaft. Additionally, all these assemblies leave the tip of the needle exposed or capable of being exposed. The tip of the needle is not locked in a completely enclosed guard.
U.S. Pat. Nos. 4,978,344 and 4,994,041, both to Dombrowski et al, disclose needle and catheter assemblies. The patents disclose a needle assembly which includes a hub for connecting the assembly to a fluid conduit, i.e., the needle. The hub includes a passageway extending therethrough to receive a hollow needle in fluid communication therewith. The cap has a neutral position along the needle adjacent to the hub for exposing a length of the needle and an extended position for capping the distal tip of the needle. The needle is disposed within a passageway of the catheter assembly whereby removal of the needle from the passageway of the catheter assembly moves the cap to the extended position capping the distal tip as the cap is unseated from the catheter assembly.